Method for improving adhesion of water-based inks to halogen-containing resin articles

ABSTRACT

Flexible and semi-rigid vinyl chloride resin compositions comprising a combination of a latent mercaptan and a zinc salt of oxidized polyethylene (a zinc ionomer) as a heat stabilizer are substantially free from the offensive odor typically associated with mercaptans and are protected during processing by the degradation products of the latent mercaptan and the zinc ionomer. The oxidized polyethylene is split out from the ionomer to act as an adhesion promoter for aqueous inks and paints, and the residual zinc carboxylate functions as a co-stabilizer with the latent mercaptan in the composition. The latent mercaptan is exemplified by a 2-S-(tetrahydropyranyl)thioalkanol., a carboxylic acid ester thereof, a 2-S-(tetrahydropyranyl)thiocarboxylic acid, an ester thereof, and the furanyl homologs of each.

FIELD OF THE INVENTION

[0001] This invention relates to improved adhesion of water-based inksand paints to articles made from heat stabilized halogen-containingresins. It relates particularly to articles of manufacture such asflexible film and semi-rigid tubing that are prepared fromheat-stabilized vinyl chloride polymers.

BACKGROUND OF THE INVENTION

[0002] Changes in heat stabilizers and in printing inks over the yearshas resulted in a loss of printability of flexible poly (vinyl chloride)substrates. The curtailment of heavy metals (e.g. cadmium) instabilizers and of volatile solvents in both stabilizers and printinginks has been held responsible for the loss of printability. Thus, therehas arisen a need for a way to enhance the wettability of such presentday PVC substrates.

[0003] A patent application by Witco Corporation published under thenumber WO96/15186 teaches that the wettability of heat-stabilized PVCfilm to water-based inks and the adherence of such inks to the film areimproved by the incorporation of oxidized polyethylene in the PVCcomposition. The heat stabilizer is a mixture of barium and zinccarboxylates having up to 20 carbon atoms in combination with organicphosphites.

[0004] The surface tension of a heavy metal-containing PVC has beenfound to be from 25 to 33% higher than that of a traditionallyplasticized PVC according to E. R. Napoleon in “Journal of Vinyl &Additive Technology”, 3, No. 2, 145 (June 1997).

[0005] As taught in co-pending, commonly assigned patent applicationSer. No. 09/133,605, filed Aug. 13, 1998, the teachings of which areincorporated herein by reference, the degradation products of a blockedor latent mercaptan present during processing of the halogen-containingresin at an elevated temperature enhance the activity of metal-basedheat stabilizers such as organotin carboxylates and mercaptides in thecomposition. Vinyl chloride resin compositions and articles made thereofare stabilized particularly well by a combination of very low levels ofzinc carboxylates and latent mercaptans selected from the groupconsisting of 2-S-(hydroxyalkylthio)-tetrahydropyran,5-S-(hydroxyalkylthio)tetrahydrofuran, 6-S-(2formylhydroxyalkylthio)tetrahydropyran, the carboxylic acid esters of said alcohols, andmixtures of said alcohols and esters. Said latent mercaptans are alsoreferred to as 2-S(tetrahydropyranyl)-thioalkanol;2-S-(tetrahydropyranyl)thioalkyl carboxylate;6-S-(2-formyl-tetrahydropyranyl)thioalkanol and carboxylates thereof,and their furanyl homologs, i.e., 5-S(tetrahydrofuranyl)thioalkanol, and5-S-(tetrahydrofuranyl)thioalkyl carboxylate.

SUMMARY OF THE INVENTION

[0006] It has now been found that a combination of such a latentmercaptan and a zinc salt of oxidized polyethylene is particularlyvaluable in that it imparts improved hydrophilicity to the surfaces ofarticles made from vinyl chloride resins as well as thermal stabilityduring high temperature processing during fabrication of such articles .The zinc salt is the only metal-containing stabilizer present during thehigh temperature processing.

[0007] It is an object of this invention, therefore, to provide a heatstabilizer composition which is free from metals other than zinc andwhich also improves the wettability of vinyl chloride resins bywater-based inks and paints.

[0008] It is another object of this invention to provide a heavymetal-free, heat stabilized halogen-containing resin having a surfacetension which is amenable to coating with a water-based ink or paint.

[0009] It is a related object of this invention to provide heatstabilized flexible, semi-rigid, and rigid PVC resin articles which haveimproved receptivity to water-based inks and paints.

[0010] It is a related object of this invention to provide novel latentmercaptans which are useful, alone or in combination with otheradditives, in heat stabilizer compositions.

[0011] These and other objects of the invention which will becomeapparent from the following description are achieved by adding a heavymetal-free heat stabilizer comprising a latent mercaptan and asynergistic amount of a zinc salt of oxidized polyethylene as the solemetal-containing stabilizer to a vinyl chloride resin and processing theresulting composition at the incipient resin decomposition temperaturewhereupon a small but hydrophilically effective amount of oxidizedpolyethylene is split from the zinc salt by liberated hydrogen chlorideand the latent mercaptan degrades to liberate a free mercaptan. Examplesof the latent mercaptan include, without limitation,2-S-(tetrahydropyranyl)thioalkanol, a carboxylate thereof, a2-S-(tetrahydropyranyl)thiocarboxylic acid or ester thereof, furanylhomologs of each, and mixtures thereof.

[0012] For the purposes of this invention, the terms blocked mercaptanand latent mercaptan are used interchangeably to mean a thioether whichdegrades during processing of the composition at an elevated temperatureto liberate a free mercaptan.

[0013] Other products of the degradation of the blocked mercaptan arebelieved to include carbocations of the blocking moiety which arestabilized by a molecular structure in which the electron deficiency isshared by several groups. Resonance stabilization and neighboring groupstabilization are two of the possible mechanisms by which thecarbocations may be stabilized. The carbocations act as intermediates inthe formation of stable compounds early in the hot processing ofhalogen-containing polymers. Although such mechanisms and the resultantcarbocations are believed to be an impetus for the liberation of theactive free mercaptan, this invention is in no way limited by theforegoing attempt to explain the working of the invention. Those skilledin the art will see the resonance stabilization and neighboring groupstabilization that are possible in the following structures of theblocked mercaptan; other mechanisms may be at work in other blockedmercaptans represented by these structures that also liberate an activefree mercaptan upon thermal and/or chemical degradation duringprocessing of polymeric compositions containing such blocked mercaptans.

DETAILED DESCRIPTION OF THE INVENTION

[0014] The vinyl chloride resins, also referred to hereinafter as PVCresins, are made from monomers consisting of vinyl chloride alone or amixture of monomers comprising, preferably, at least about 70% by weightof vinyl chloride, based on the total monomer weight. Examples of thecopolymers include those made from vinyl chloride and from about 1 toabout 30% of a copolymerizable ethylenically unsaturated material suchas vinyl acetate, vinyl butyrate, vinyl benzoate, vinylidene chloride,diethyl fumarate, diethyl maleate, other alkyl fumarates and maleates,vinyl propionate, methyl acrylate, 2-ethylhexyl acrylate, butyl acrylateand other alkyl acrylates, methyl methacrylate, ethyl methacrylate,butyl methacrylate and other alkyl methacrylates, methylalpha-chloroacrylate, styrene, trichloroethylene, vinyl ketones such asvinyl methyl ketone and vinyl phenyl ketone, 1-fluoro-2-chloroethylene,acrylonitrile, chloroacrylonitrile, allylidene diacetate,chloroallylidene diacetate, and vinyl ethers such as vinyl ethyl ether,vinyl chloroethyl ether, vinyl phenyl ether, and the vinyl ether ofethoxytetrahydropyran prepared by the reaction of one mole of acroleinwith one mole of ethylene glycol divinyl ether. Typical copolymersinclude vinyl chloride-vinyl acetate (96:4 sold commercially as VYNW),vinyl chloride-vinyl acetate (87:13), vinyl chloride-vinylacetate-maleic anhydride (86:13:1), vinyl chloride-vinylidene chloride(95:5); vinyl chloride-diethyl fumarate (95:5), and vinyl chloride2-ethylhexyl acrylate (80:20).

[0015] As used herein, the term PVC composition means a compositioncomprising a vinyl chloride resin. A rigid PVC composition is one whichdoes not contain a plasticizer. A semi-rigid PVC composition is onewhich contains from 1 to about 25 parts of a plasticizer per 100 partsby weight of the vinyl chloride resin. A flexible PVC compositioncontains from about 25 to about 100 parts per 100 parts by weight (phr)of the vinyl chloride resin. Alkyl esters of carboxylic acids in whichthere are from 1 to 3 alkyl groups having from 8 to 12 carbon atoms arerepresentative of the plasticizers. The alkyl group may be n-octyl,2-ethylhexyl, nonyl, decyl, or dodecyl. Suitable esters includephthalates, trimellitates, benzoates, adipates, glutarates, andsebacates. The plasticizer may also be a pentaerythritol or such anester thereof. A polymeric plasticizer is also suitable.

[0016] As used herein, an acyloxyalkyl radical originates from acarboxylic acid ester of an alkyl alcohol. Therefore, the R¹ radical ofthe stearic acid ester of mercaptopropanol, as represented by theformula below, is the stearoyloxypropyl radical; likewise, the R¹radical of the oleic acid ester of mercaptopropanol, which is one of thetallate esters of that alcohol, is the oleoyloxypropyl radical.

[0017] As used herein, substantially means largely if not wholly thatwhich is specified but so close that the difference is insignificant.

[0018] One of the advantages of this invention is that the offensiveodor of mercaptans is masked by a blocking group so that the latentmercaptan thus created may be put into a PVC composition or the likewith little or no offense to the operator with the knowledge that thefree mercaptan will be released as a degradation product when thetreated composition is heated during the usual processing, e.g.extrusion. It is believed that the free mercaptan is consumed as it isliberated in response to the evolution of hydrogen chloride at theincipient decomposition temperature of the vinyl chloride resin.

[0019] The blocking compounds are preferably those which are capable offurnishing a stabilized carbocation having a molecular structure inwhich the electron deficiency is shared by several groups. Resonancestabilization and neighboring group stabilization are two of thepossible mechanisms by which the carbocations may be stabilized.Blocking compounds such as 3,4-dihyropyran and 2,3-dihydrofuran arepreferred for the purposes of this invention.

[0020] The blocked mercaptans suitable for the purposes of thisinvention are represented by the following formula:

[0021] wherein a is 1, m is 0, and n is 0 or 1; y=1 to 4; R¹ is R′C(O)OHwherein R′ is alkylene; or R¹ is an alkyl, pentaerythrityl, alkylene,cycloalkyl, cycloalkylene, aryl, alkaryl, aralkyl, aralkylene,hydroxyalkyl, dihydroxyalkyl, alkoxyalkyl, acyloxyalkyl,hydroxy(polyalkoxy)alkyl, hydroxy(polyalkoxy)acyl,acyloxy(hydroxyalkyl), acyloxy(alkoxyalkyl), acyloxy(polyalkoxy)alkyl,acyloxy(polyalkoxy)acyl, alkoxyacyl, oxy[bis(alkoxyacyl)],oxy[bis(polyalkoxyacyl)], benzoyloxy(polyalkoxy)alkyl,benzoyloxy(polyalkoxy)acyl, or alkylene bis-(acyloxyalkyl),thio-bis-[alkoxyacyl], dithio-bis-[alkoxyacyl], alkoxy(polyalkoxy)acyl,hydroxyalkoxyalkyl, alkoxy(hydroxyalkyl) alkoxy(polyalkoxy)alkyl,mercaptoalkyl, mercaptoalkylene, mercaptoalkoxyacyl,tetrahydopyranyloxy(polyalkoxy) acyl, tetrahydropyranyloxyalkyl,hydroxyaryl, or mercaptoaryl radical, said alkyl, alkylene, alkoxy, andacyl radicals having from 1 to 22 carbon atoms; R², R³, R⁴, R⁵, R⁶, andR⁷ are independently hydrogen, a hydroxyl, mercapto, alkyl, alkylene,acyl, aryl, haloaryl, alkaryl, aralkyl, hydroxyalkyl, alkenyloxyalkoxy,alkoxy, aryloxy, alkaryloxy, mercaptoalkyl, hydroxyalkylmercapt.oalkyl,mercaptoalkylene, hydroxyaryl, alkoxyaryl, alkoxyhydroxyaryl,arylcarbonyl, or mercaptoaryl radical having from 1 to 22 carbon atoms;X is a heteroatom selected from the group consisting of oxygen andsulfur, and one or both of the R³ and R⁵ alkylene radicals joins with R⁷and X to form a heterocyclic moiety with X as the heteroatom.

[0022] The mercaptans useful in this invention include the well-knownmercaptoalkanols and the carboxylate esters thereof, including, but notlimited to, the following compounds:

[0023] wherein R¹⁰ and R¹⁹ are independently OH, —O(C═O)R¹⁷

[0024] —(C═O)OR¹⁷, —SH, aryl, C₁, to C₁₈ alkyl, and —H; R¹¹ is —H, aryl,or C₁ to C₁₈ alkyl; R¹⁷ is —H, alkyl, alkenyl, aryl, aralkyl, alkaryl,cycloalkyl, or cycloalkylenyl; wherein i=0 or an integer from 1 to 6inclusive.

[0025] Mercaptan-containing organic compounds preferred as intermediatesin the preparation of the latent mercaptans of this invention are thosecompounds according to formula (MC1) where R¹¹ is —H, R¹⁹ is —H, R¹⁰ is—O(C═O) R¹⁷ or —(C═O)OR ¹⁷, and i=1; and those compounds according toformula (MC3) where R¹¹ is —H and i=1.

[0026] Examples of mercaptan-containing compounds described by the aboveformulas include, but are not limited to, the following compounds:

[0027] In general, the procedure for making the latent mercaptans whichare useful in this invention comprises adding the mercapto group of thefree mercaptan across the double bond of a polarized, unsaturatedcompound as follows:

[0028] To a stirred mixture, under nitrogen atmosphere, of themercaptan, acid catalyst, and optionally, a small percentage ofantioxidant to inhibit radical reactions, is added dropwise to thepolarized, unsaturated compound, either neat or in solution, whilemaintaining the temperature between 10-70° C. The mixture or solution isthen heated for between 1 and 6 hours at 35°-70° C. and conversion toproduct is monitored by gas chromatography and iodine titration for SH.The acid catalyst is removed by an alkaline wash and the resultingproduct is dried with magnesium sulfate and filtered. The solvent, ifrequired, is removed under reduced pressure at <50° C. to yield thelatent mercaptan. A solid phase catalyst may be used and then filteredout of the reaction mixture and regenerated for use in a subsequentsynthesis, In this way, a wash step is eliminated. This generalizedprocedure is referred to hereinafter as Procedure A.

[0029] In accordance with Procedure A, for example, mercaptoethanol isadded across the double bond of N-vinylcaprolactam to yieldN-2-hydroxyethylthioethylcaprolactam. Mercaptoethyldecanoate (ormercaptoethylcaproate) reacts with 3,4-dihydropyran in that procedure togive 2-S-(tetrahydropyranyl)thioethyldecanoate.Bis(hydroxyethylthioethyl) cyclohexyl ether is made from themercaptoethanol and cyclohexyl di-vinyl ether. In like manner, thecorresponding caprate, oleate, and tallate esters form the correspondingcyclohexyl ethers. Also, indene is converted by the addition of themercaptoethanol to 2H-dihydroindenylthio-ethanol.

[0030] A generalized procedure for the condensation of a free mercaptanwith a labile halogen-containing compound is as follows:

[0031] To a stirred mixture of the mercaptan and halogen-containingcompound under nitrogen atmosphere is added dropwise a solution ofsodium methoxide in methanol while maintaining the temperature below 50°C. Optionally, the reaction is allowed to proceed without the additionof a base source and the liberated hydrogen chloride is removed bynitrogen gas sweep and neutralized with the use of an external acidscrubber. The mixture or solution is then heated for between 2 to 24hours at 50°-70° C. and conversion to product is monitored by gaschromatography and iodine titration for % SH. The product is thenneutralized, washed with water, dried with magnesium sulfate, andfiltered. The solvent, if required, is removed under reduced pressure at<50° C. to yield the latent mercaptan. This generalized procedure isreferred to hereinafter as Procedure B.

[0032] A generalized procedure for the condensation of a free. mercaptanwith a labile hydroxyl-containing compound is as follows:

[0033] To a stirred solution of the mercaptan, acid catalyst, andsolvent under nitrogen atmosphere is added the hydroxy-containingcompound either neat or in solution while maintaining the temperature<45° C. The solution is then heated to 45°-75° C. for between 1 to 10hours and conversion to product is monitored by gas chromatography andiodine titration for % SH. Optionally, an azeotropic solvent is chosenfor removal of reaction water by an appropriate means at refluxtemperatures, typically 60°-120° C. Completion of reaction is achievedafter the theory amount of water has been collected. The acid catalystis removed by alkaline wash and the resulting solution is dried withmagnesium sulfate and filtered. The solvent is removed under reducedpressure at <55° C. to yield the latent mercaptan. This procedure isreferred to hereinafter as Procedure C.

[0034] For example, 2-hydroxybenzyl alcohol condenses withmercaptoethanol in accordance with Procedure C to form1-(2-hydroxyphenyl)-1-S-(2-hydroxyethylthio)methane.

[0035] A generalized procedure for the reaction of a free mercaptan witha glycidyl ether is as follows:

[0036] To a stirred mixture of the mercaptan and acid catalyst undernitrogen atmosphere is added the glycidyl ether, either neat or insolution, while maintaining the temperature between 25°-60° C. Themixture or solution is then heated to between 50°-75° C. for a period of1 to 6 hours and conversion to product is monitored by gaschromatography and iodine titration for % SH. The acid catalyst isremoved by alkaline wash, the resulting product is dried with magnesiumsulfate, and filtered. The solvent, if required, is removed underreduced pressure at <55° C. to yield the latent mercaptan. For example,the reaction between mercaptoethanol and glycidyl neodecanoate givesC₉H₁₉C(═O)OCH₂CH(OH)CH₂SCH₂CH₂OH. This procedure is referred tohereinafter as Procedure D.

[0037] A generalized procedure for the condensation of a free mercaptanwith an aldehyde is as follows:

[0038] To a stirred solution of the mercaptan, acid catalyst, andazeotropic solvent under nitrogen atmosphere is added the aldehyde withheating to reflux, typically between 65°-120° C., for removal ofreaction water. Completion of reaction is achieved after the theoryamount of water has been collected. Optionally, to a stirred solution ofmercaptan, aldehyde, and ether is added BF₃-etherate dropwise underreflux conditions. The solution is refluxed for between 1 to 6 hours andconversion to product is monitored by gas chromatography. The acidcatalyst is removed by alkaline wash, the solution is dried withmagnesium sulfate and filtered. The solvent is removed under reducedpressure at <65°C. to yield the latent mercaptan. This generalizedprocedure is referred to hereinafter as Procedure E.

[0039] The polarized, unsaturated compounds are exemplified by3,4-dihydropyran; 3,4-dihydro-2-methoxy-2H-pyran;3,4-dihydro-2ethoxy-2H-pyran; 3,4-dihydro-2-methoxy-2H-pyran;3,4-dihydro-2formyl-2H-pyran; 3,4-dihydro-3-methoxy-2H-pyran; and 2,3-dihydrofuran. The 3,4-dihydro-2-formyl-2H-pyran is made by theDiels-Alder dimerization of acrolein at high temperatures and pressures.The 3,4-dihydro-2-alkoxy-2H-pyrans and 3,4-dihydro-2phenoxy-2H-pyran aremade by the reaction of the corresponding vinyl ether with acrolein inthe presence of a catalytic amount of a zinc salt, e.g., zinc chloride.A variety of 3,4-dihydro-2H-pyrans having a substituent in the2-position can be made by similar reactions. The products formed by thereaction of 1 and 2 moles of acrolein with the divinyl ether of analkylene-or polyalkylene glycol are blocking agents, also. In the caseof the reaction of two moles of acrolein per mole of a divinyl ether,latent mercaptans made from the resulting di-(3,4-dihydropyranyl) ethersalso have the potential of being chelating agents in the polymercompositions of this invention. The reaction of one mole of acroleinwith one mole of the divinyl ether forms a monomer which may becopolymerized with vinyl chloride with or without a wide variety ofethylenically unsaturated compounds. The product from the reaction ofacrolein with chloroethyl vinyl ether provides a substituted3,4-dihydropyran that can be further derivatized.

[0040] A stabilizer composition of this invention may be made quiteconveniently by the addition of a mercaptan across the double bond ofthe pyran ring in the presence of zinc chloride as a catalyst for theaddition and as a synergistic stabilizer in the product.

[0041] Examples of 2-S-(tetrahydropyranyl)thioalkanols that are suitableas latent mercaptans for this invention include, without limitation,2-S-(tetrahydropyranyl)thioethanol, 2-S-(tetrahydropyranyl)thiopropanol,and 2-S-(tetrahydropyranyl)-thiobutanol6-S-(2-forTnyl-tetrahydropyranyl)thioethanol, and their furanylhomologs, e.g., 5-S-(tetrahydrofuranyl)thioalkanol. The carboxylatessuitable for the purposes of this invention. are exemplified by2-S-(tetrahydropyranyl.)th.ioethyl caprate, which also may be named2-S-(2-decanoyloxyethylthio) tetrahydropyran, made by the reactionbetween mercaptoethyl caprate and 3,4-dihydropyran according to theforegoing procedure and has the following formula:

[0042] Homologs of the thus described compounds which are particularlyuseful in. the stabilization of flexible PVC compositions include the2-S-(tetrahydropyranyl)thioalkyl carboxylates and their furanyl homologswherein the ethyl moiety is replaced by propyl, butyl, hexyl, and othersin the series up to and including dodecyl and the capric acid radical ofsaid compound is replaced by other fatty acid radicals (saturated andunsaturated) or resin acid radicals having up to and including 22 carbonatoms. The acids are exemplified by caproic, caprylic, lauric, myristic,palmitic, stearic, arachidic, behenic, and the oleic and linoleic acids,as such, or as found in tall oil acids along with abietic and pimaricacids. The mercaptoalkyl carboxylate moiety is thus exemplified bymercaptoethyl laurate, mercaptoethyl oleate, mercaptoethyl hexanoate,mercaptoethyl octanoate, mercaptoethyl myristate, mercaptoethylpalmitate, mercaptoethyl stearate, mercaptoethyl oleate, mercaptoethyllinoleate, and the mercaptopropyl, mercaptobutyl, and mercaptooctylhomologs of each of the above. The esters are made by the conventionalmethod of reacting the hydroxyl group of a mercaptoalkanol with thedesired carboxylic acid in the presence of an acidic catalyst andremoving water as it forms.

[0043] When 2-S-tetrahydopyranylthioethanol is prepared from3,4-dihydropyran by said procedure, by-products having the followingformulas are also obtained:

[0044] The homologous by-products are expected when 2,3-dihydrofuran isreacted with mercaptoethanol but the principal product is the5-S-tetrahydrofuranylthioethanol shown by the following structure:

[0045] When the 3,4-dihydropyran is replaced by a3,4-dihydro-2-alkoxy-pyran; a 3,4-dihydro-2-phenoxy-pyran; or a3,4-dihydro-2-formyl-pyran in the above procedure, the followingproducts are formed:

[0046] A 2-S-(tetrahydropyranyl)mercaptoalkyl carboxylate is more activeas a heat stabilizer in flexible PVC compositions than thetetrahydropyranyl-blocked mercaptans derived from alkylmercaptans suchas dodecanethiol when activated according to this invention as manifestin the improved color hold properties and dynamic thermal stability ofsuch stabilized PVC compositions. The higher activity may be the resultof the better compatibility of the ester-containing latent mercaptanswith a plasticized PVC. The compatibility of the correspondinghomologous furan-based latent mercaptans is similar.

[0047] As used herein, a zinc ionomer is defined as a salt in which bothof the zinc valences are paired with carboxylate anions from theoxidized polyethylene, a mixed salt in which one of the zinc valences ispaired with a carboxylate ion having from 7 to 18 carbon atoms and theother is paired with a carboxylate ion from an oxidized polyethylene, ora physical mixture of a zinc salt of a carboxylic acid having from 7 to18 carbon atoms and a zinc salt an oxidized polyethylene. For thepurposes of this invention, the oxidized polyethylene has a molecularweight of at least about 750 and up to about 2100. The oxidizedpolyethylenes have from about 50 to about 150 carbon atoms and arebelieved to have hydroxyl and ketonic substituents along the polymerchain as well as carboxylic groups. The acid number ranges from about 2to about 50. The melting point of the oxidized polyethylene ispreferably from about 60° C. to 150° C. (140-302° F.) so that it issolid at the temperatures at which vinyl chloride resins are normallyused. A preferred oxidized polyethylene, sold by Allied-Signal Corp. asAC629A, has molecular weight of about 2000, a softening point in the213-221° F. (101-105° C.) range, and an acid number of 14-17.

[0048] The carboxylic acids that are useful along with the oxidizedpolyethylene may be aliphatic, arylaliphatic, aromatic, oralkylaromatic; the aliphatic moieties have a straight or branched chainstructure and may be saturated or unsaturated. Thus, the mixed salt mayinclude an anion from, for example, heptanoic, octanoic (or caprylic),2-ethylhexanoic, decanoic (or capric), lauric, oleic, stearic, benzoic,phenylacetic, or methylbenzoic acid. An ionomer wherein the octanoateand the oxidized polyethylene fulfill the zinc valences is an example ofa preferred latent wetting agent for the vinyl chloride resin.

[0049] The stoichiometric amount of zinc oxide, zinc chloride, or a zinccarboxylate/chloride is reacted with the oxidized polyethylene toprepare the desired zinc salt. The zinc carboxylate/chloride is preparedfrom zinc chloride and less than the stoichiometric amount of thedesired carboxylic acid so that the remaining chloride ions may reactwith the oxidized polyethylene to form a mixed salt as an ionomer usefulin this invention. An ionomer is also made by the stepwise reaction ofthe zinc oxide with the oxidized polyethylene and, for example, octanoicacid or by a one step reaction with a mixture of the oxidizedpolyethylene and octanoic acid.

[0050] The adhesion promoting stabilizer compositions of this inventionconsist essentially of from about 40% to about 98%, preferably fromabout 60% to about 80% of a latent mercaptan and from about 2 to about60%, preferably from about 20 to about 40%, of the zinc ionomer, basedon the total weight of the stabilizer composition. The latent mercaptanis exemplified by 2-S- (tetrahydropyranyl)thioalkanol, a carboxylatethereof, a 2-S-(tetrahydrofuranyl)-thioalkanol, a carboxylate thereof, a2-S-(tetrahydropyranyl)thiocarboxylic acid, an ester thereof, a2-S-(tetrahydrofuranyl)thiocarboxylic acid, an ester thereof, and amixture of two or more of said alkanols, acids, and esters. They areparticularly suited to impart superior stabilization against thedeteriorative effects of heat and ultra-violet light on flexible PVCresins in comparison with stabilizer compositions previously known inthe art. They may be prepared by blending the components thereof in anyconvenient manner which produces a homogeneous mixture, such as byshaking or stirring in a container. Likewise, the stabilizercompositions of this invention can be incorporated in a vinyl chlorideresin in an appropriate mill or mixer or by any other of the well-knownmethods which provide uniform distribution of the stabilizer throughoutthe polymer composition.

[0051] It will be readily apparent to one of ordinary skill in the art,that the precise amount of stabilizer composition added to the vinylchloride resin will depend upon several factors, including, but notlimited to, the particular resin employed, the temperature to which theresin will be subjected, and the possible presence of other stabilizingcompounds. In general, the more severe the conditions to which the resinis subjected, and the longer the term required for resistingdegradation, the greater will be the amount of stabilizer compositionrequired. Generally, the stabilizer composition is used in an amount toprovide as little as about 0.20 part and as much as about 5 parts byweight of the latent mercaptan per hundred parts by weight (phr) of thePVC resin. While there is no critical upper limit to the amount oflatent mercaptan which can be employed, amounts up to about 3.0 phr ofthe PVC resin are preferred. The zinc salt of oxidized polyethylene isused in an amount effective to improve the wettability to water-basedpaints and inks of an article formed from the vinyl chloride resin. Fromabout 0.2 to about 2.5 phr is suitable, but from 0.5-1.5 phr ispreferable.

[0052] In addition to the stabilizer compositions of this invention, thePVC resin compositions of this invention may contain plasticizers, asmentioned above in regard to semi-rigid and flexible PVC, as well aspigments, fillers, antioxidants, blowing agents, dyes, ultraviolet lightabsorbing agents, densifying agents, biocides, and the like.

[0053] Conventional non-metallic stabilizers can also be included in thePVC resin compositions of the present invention. Thus, there can beincluded 0.01-0.75%, based on the weight of the resin, of sulfurcontaining compounds such as dilaurylthiodipropionate, distearyl3,3′-thiodipropionate, dicyclohexyl-3,3-thiodipropionate,dioleyl-3,3′-thiodipropionate, dibenzyl-3,3′-thiodipropionate,didecyl-3,3′-thiodipropionate, dibenzyl-3,3′-thiodipropionate,diethyl-3,3′-thiopropionate, lauryl ester of 3-methylmercaptopropionicacid, lauryl ester of 3-butylmercaptopropionic acid, lauryl ester of3-lauryl mercaptopropionic acid, and phenyl ester of 3-octylmercaptopropionic acid.

[0054] Likewise there can be included from 0.01-10% by weight of thevinyl chloride polymer of a polyol stabilizer for vinyl chloride resins.Thus there can be included glycerol, sorbitol, pentaerythritol, mannitoland polyethers such as diethylene glycol, triethylene glycol,tetraethylene glycol, tripropylene glycol, and the like.

[0055] Nitrogen containing stabilizers such as dicyandiamide, melamine,urea, formoguanamine, dimethyl hydantoin, guanidine, thio-urea,2-phenylindoles, aminocrotonates, N-substituted maleimides, uracil, the1,3-dialkyl-6-amino-uracil derivatives described in GermanOffenlegungsschrift 19,741,778 by Ciba Specialty Chemicals Holding Inc.,and the pyrrolodiazine diones described in published Australian PatentApplication No. AU-A-48232/96 by Ciba-Geigy, and the like may also beincluded in the compositions of this invention in amounts of 0.1-10% byweight.

[0056] The 1,3-dialkyl-6-amino-uracils and 1,3-dialkyl-6-phenylaminouracils are prepared by known methods such as those taught in U.S. Pat.No. 2,598,936, which is incorporated herein by reference. Other uracilssuitable for use in this invention have substituents such ashydroxyalkyl, alkoxyalkyl, hydroxyphenyl, etc. and are taught in U.S.Pat. No. 4,656,209, which is incorporated herein by reference, also.They, also, may be made according to the procedures of the '936 patent.Their structure is illustrated by the following formula:

[0057] wherein R*, and R**, are independently hydrogen, alkyl,hydroxyalkyl, or alkoxyalkyl, and R*** is hydrogen, alkyl, phenyl, orhydroxyphenyl, wherein each of the alkyl moieties have from 1 to 4carbon atoms.

[0058] Of particular interest are the pyrrolodiazine diones described bythe formula:

[0059] wherein R^(⋄), R^(2⋄)R^(3⋄), and R^(4⋄) are independentlyhydrogen or C_(1—C) ₄ alkyl. Examples of compounds contemplated for usein this invention include the1H-pyrrolo[2,3-d]pyrimidine-2,4(3H,7H)-diones exemplified by CompoundNos. 103, 111, 123, 129, and 131 of said Australian Patent Application,which have the following substituents:

[0060] No. 103 1,3,6-trimethyl;

[0061] No. 111 1,3,6,7-tetramethyl.;

[0062] No. 123 none;

[0063] No. 129 1,3-diethyl,6-methyl;

[0064] No. 131 1,3-di-n-butyl,6-methyl;

[0065] Said compounds may be prepared by the method described by S.Senda and K. Hirota, Chem. Pharm. Bull., 22(7), 1459-1467(1974) or bythe reaction of the corresponding aminouracil with molar excesses ofchloroacetaldehyde and ammonium acetate in water at about 65° C. until aprecipitate forms or with molar excesses of acetoxyacetone and ammoniumacetate in water at reflux for 12 hours.

[0066] An anti-oxidant may be added in an amount of 0.01-10%, preferably0.1-5% by weight of the PVC resin. Phenolic antioxidants areparticularly suitable and are exemplified by 2,6-di-t-butyl-p-cresol,butylated hydroxyanisole, propyl gallate,4,4′-thiobis(6-t-butyl-m-cresol), 4,4′-cyclohexylidene diphenol,2,5-di-t-amyl hydroquinone, 4,4′-butylidene bis(6-t-butyl-m-cresol),hydroquinone monobenzyl ether, 2,2′-methylene-bis(4-methyl-6-t-butylphenol), 2,6-butyl-4-decyloxy phenol, 2-t-butyl-4-dodecyloxy phenol,2-t-butyl-4-dodecyloxy phenol, 2-t-butyl-4-octadecyloxy phenol,4,4′-methylene-bis(2,6-di-t-butyl phenol), p-amino phenol,N-lauryloxy-p-amino phenol, 4,4′-thiobis(3-methyl-6-t-butyl phenol), bis[o-(1,1,3,3-tetramethyl butyl)phenol] sulfide, 4-acetyl-β-resorcylicacid, A-stage p-t-butylphenolformaldehyde resin,4-dodecyloxy-2-hydroxybenzophenone, 3-hydroxy-4- (phenylcarbonyl) phenylpalmitate, n-dodecyl ester of 3-hydroxy-4-(phenyl carbonyl)phenoxyacetic acid, and t-butyl phenol.

[0067] From 0.01-30% by weight of an epoxy compound, based on the weightof the vinyl chloride polymer in the PVC cornpositions of this inventionmay also be used. Examples of such epoxy compounds include epoxidizedsoya bean oil, epoxidized lard oil, epoxidized olive oil, epoxidizedlinseed oil, epoxidized castor oil, epoxidized peanut oil, epoxidizedcorn oil, epoxidized tung oil, epoxidized cottonseed oil,epichlorhydrin/bis-phenol A resins, phenoxy-propylene oxide,butoxypropylene oxide, epoxidized neopentylene oleate, glycidylepoxystearate, epoxidized α-olefins, epoxidized glycidyl soyate,dicyclopentadiene dioxide, epoxidized butyl toluate, styrene oxide,dipentene dioxide, glycidol, vinyl cyclo-hexene dioxide, glycidyl etherof resorcinol, glycidol ether of hydroquinone, glycidyl ether of1,5-dihyroxynaphthalene, epoxidized linseed oil fatty acids, allylglycidyl ether, butyl glycidyl ether, cyclohexane oxide,4-(2,3-epoxypropoxy) aceto-phenone, mesityl oxide epoxide,2-ethyl-3-propyl glycidamide, glycidyl ethers of glycerine,pentaerythritol and sorbitol, and 3,4-epoxycyclohexane-1,1-dimethanolbis-9,10-epoxystearate.

[0068] Likewise there can be used organic phosphites in an amount of0.01 to 10%, preferably 0.1-5% by weight of the vinyl chloride polymer.The organic phosphites contain one or more, up to a total of three,aryl, alkyl, aralkyl and alkaryl groups, in any combination. The term“trialkylaryl” is inclusive of alkyl, aryl, alkaryl and aralkylphosphites containing any assortment of alkyl, aryl, alkaryl and aralkylgroups. Exemplary are triphenyl phosphite, tricresyl phosphite,tri(dimethylphenyl) phosphite, tributyl phosphite, trioctyl phosphate,tridodecyl phosphite, octyl diphenyl phosphite, dioctyl phenylphosphite, tri(octyl-phenyl) phosphite, tri(nonylphenyl) phosphite,tribenzyl phosphite, butyl dicresyl phosphite, octyl di(octyl-phenyl)phosphite, tri(2-ethyl-hexyl) phosphite, tritolyl phosphite,tri(2-cyclohexylphenyl) phosphite, tri-alpha-naphthyl phosphite,tri(phenylphenyl) phosphite, and tri(2-phenylethyl) phosphite.

[0069] Conventional lubricants for vinyl chloride resins such as lowmolecular weight polyethylene, i.e. polyethylene wax, fatty acid amides,e.g. lauramide and stearamide, bisamides, e.g. decamethylene bis amide,and fatty acid esters, e.g. butyl stearate, glyceryl stearate, linseedoil, palm oil, decyloleate, corn oil, cottonseed oil, hydrogenatedcottonseed oil, stearic acid, calcium stearate, mineral oil, montan wax,and the like can also be included.

[0070] The latent mercaptans having the following formula (Formula 2 areconsidered to be novel compositions of matter that are useful with orwithout the zinc ionomers as a heat-stabilizer for halogen-containingpolymers

[0071] wherein a is 0 or 1, m is 0 or 1, and n is 0 or 1; y=1 to 4, wheny=1, z is 1 to 4, when y is more than 1 z is 1; R¹ is R′C(O)OH whereinR′ is an alkylene radical, or R¹ is a thio-[bis(alkoxyacyl)],dithio-[bis(alkoxyacyl)], pentaerythrityl, alkenyloxy(polyalkoxy)alkyl,oxy[bis(alkoxyacyl)], oxy[bis(polyalkoxyacyl],benzoyloxy(polyalkoxy)alkyl, or benzoyloxy(polyalkoxy)acyl radical, saidalkyl, alkylene, and acyl radicals having from 1 to 22 carbon atoms; R²,R³, R⁴, R⁵, R⁶, and R⁷ are independently hydrogen, a hydroxyl, mercapto,alkyl, alkylenyl, acyl, aryl, haloaryl, alkaryl, aralkyl, hydroxyalkyl,chloroalkoxy, alkylene, alkenyloxyalkoxy, alkoxy, aryloxy, alkaryloxy,mercaptoalkyl, hydroxyalkylmercaptoalkyl, mercaptoalkylenyl,hydroxyaryl, alkoxyaryl, alkoxyhydroxyaryl, arylcarbonyl, ormercaptoaryl radical having from 1 to 22 carbon atoms; X is aryl,haloaryl, alkaryl, hydroxyaryl, dihydroxyaryl, aralkaryl, alkoxyaryl,arylcycloalkyl, or a heteroatom selected from the group consisting ofoxygen and sulfur, with the option that one or both of the R³ and R⁵alkylenyl radicals joins with R⁷ and X to form a heterocyclic moietywith X as the heteroatom.

[0072] It has also been found that a one-component PVC stabilizer isobtained from the latent mercaptans of Formula 1 and Formula 2 whereinR¹ is pentaerythrityl by forming a complex with a zinc halide. Forexample, a zinc halide forms a complex with a pair of neighboringhydroxyl groups in a latent mercaptan such as the adduct of 2 moles of3,4-dihydropyran with one mole of the diester of pentaerythritol and amercaptocarboxylic acid such as thioglycolic acid or mercaptopropionicaci.d. The one-component PVC stabilizer is pre-formed or formed in situby complexing a zinc halide, preferably the chloride, with such a latentmercaptan as shown by the following formula:

[0073] wherein Hal is a halogen ion, preferably a chloride ion. Thepreparation of blocked mercaptans and zinc salts used in the adhesionpromoting stabilizers of this invention, the preparation of saidstabilizers, and the advantages of compositions comprising saidstabilizers are illustrated as follows.

Preparation of 2-S- (tetrahvdropyranvl) thioethvlcaprate

[0074]¹H-NMR spectroscopy was used to determine the molecular structureof 2-S-(decanoyloxyethylthio)tetrahydropyran or2-S(tetrahydropyranyl)thioethylcaprate which was prepared by adding 42.0grams (0.50 mole) of 3,4-dihydropyran to 112.2 grams (0.50 equivalent)of mercaptoethylcaprate (14.7% SH) in the presence of an acid catalystover a period of 45 minutes while maintaining a nitrogen atmosphere anda temperature below 35° C. and then heating it to 50° C. and holdingthat temperature for 1.5 hours. After cooling the solution, it waswashed with two 200 ml portions of a 10% sodium bicarbonate solution inwater, followed by a 200 ml wash with water. The organic layer was driedwith MgSO₄ to yield a light yellow liquid having an SH content of lessthan 0.5 percent as determined by titration with a 0.100 N iodinesolution in isopropanol. The ¹H-NMR (CDCl₃, δ) spectrum was: 2.3 (2H, t,—C(═O)—CH ₂—CH₂), 2.8 (2H, m, —S—CH ₂—CH₂—), 4.2 (2H, m, —S—CH₂CH ₂—O—),4.9 (1H, m, —O—CH(—S—CH₂—)—CH₂—CH₂—). The total color change (dE) of aPVC composition containing 0.13 phr of the latent mercaptan of thisexample was measured versus a white tile standard using a Huntercolorimeter at one minute intervals. At one minute, it was 4.2; at fiveminutes, it was 8.4.

Preparation of 2-S-tetrahvdropyranyl) thioethyltallate

[0075] 2-S-tetrahydropyranyl) thioethyltallate was prepared by adding172.45 grams (2.05 equiv.) of 3,4-dihydro(2H)pyran dropwise to 760.00grams (2.00 equiv.) of 2-mercaptoethyltallate (8.70% SH by iodometrictitration) containing 0.93 gram of methanesulfonic acid (70% active)over a period of 45 minutes under a nitrogen blanket and a temperaturebetween 25-35° C. and heating to 35-40° C. for 2 hours. After coolingthe solution, 3 grams of Norite carbon black was charged and the productwas vacuum filtered to yield 932 grams of yellow liquid having a SHcontent of less than 0.4% as determined by titration with 0.100 N iodinesolution in isopropanol. The ¹H-NMR(CDC13, δ) spectrum was: 2.3 (2H, t,—C(═O)—CH ₂—CH₂—), 2.8 (2H, m, —S—CH ₂—CH₂—), 4.3 (2H, m,(—CC(═O)—O—CH₂), 4.9 (1H, m, —O—CH(—S—CH₂)—CH₂—CH₂—). GC of the product (1% in ether)indicated one primary product peak at 26.3 minutes retention time(50-300° C.; 10° C./min.; split flow injector/FID). The. product isreferred to in Table 1 below as DHP/2-MET.

Preparation of a Zinc Ionomer

[0076] To a 250 ml flask fitted with a side-arm condenser there wascharged with stirring 50 grams (0.0143 equivalent) of oxidizedpolyethylene (Allied Signal AC-629A), 175 ml of butyl carbitol, 1.16grams (0.0286 equivalent) of 99% pure zinc oxide, and 2.06 grams (0.0143equivalent) of 99% pure octanoic acid. The reaction mixture was thenheated to 75° C. (167° F.) and 3 drops of glacial acetic acid were addedbefore the temperature was raised to 120-125° C. (248-257° F.) for 20minutes. The mixture was stripped of water and solvent by applying avacuum of 3 mm Hg at that temperature. The product is a cream-coloredwax which has a zinc content of 1.8% (measured as the metal) accordingto atomic absorption analysis. The theoretical zinc content is 1.8%. Theproduct is referred below as ZNION.

EXAMPLE 1

[0077] A mixture of 5.2 grams of the above zinc ionomer and 20.8 gramsof 2-S-tetrahydropyranyl-thioethyl tallate was heated in a 50 mlErlenmeyer flask to 85° C. to obtain a homogeneous dispersion. Whencooled, the product is a soft paste having a zinc content of 0.4% as themetal. The product is referred to in Table below as ZNPM#1.

EXAMPLE 2

[0078] A general flexible PVC composition containing: INGREDIENT AMOUNTPVC resin (k = 70) 100.0 parts Dioctyl phthalate  40.0 phr Epoxidizedsoybean oil  5.0 phr Stearic acid  0.2 phr Stabilizer See Table 1

[0079] was processed on a dynamic two-roll mill (roll speeds 30R/40R) at350° F. with chips taken at five minute intervals to a maximum of 60minutes. The yellowness index of the chips was measured using a HunterLabs Colorimeter (L, a, b) for comparison in Table II. The dynamicthermal stability (DTS) of the compositions was measured on a BrabenderPlasti-Corder PL-2100 rheometer at 200° C./80 rpm with No. 6 rollerblades and an electric head. The DTS, shown in Table 3, was recorded asthe elapsed time in minutes before a sharp upturn in the torque curveduring processing was observed. The DTS value is considered to be thetime at which degradation of the PVC began. TABLE 1 Example StabilizerAmount (phr) 2 ZNPM#1 2.5 3 DHP/2-MET 2.0 and ZNION 0.5 added separatelyControl #1 DHP/2-MET 2.5 Control #2 ZNION 0.5 Comp Ex 1 AKZO INTERSTABCZ-11 2.5 Comp Ex 2 FERRO THERM-CHEK 760X 2.5

[0080] TABLE 2 PVC Color Hold (Yellowness Index) Minutes Time\ Ex. 5 1015 20 25 30 35 40 45 50 55 60 2 11.6 13.9 17.1 19.3 20.0 23.1 26.0 30.933.1 36.3 41.6 49.6 3 11.5 12.8 13.4 15.4 16.6 17.8 22.3 27.0 31.5 35.944.4 52.8 Con 1 46.5 78.7 87.8 89.9 88.6 91.8 99.1 101.9 106.7 106.2113.5 112.1 Con 2 21.8 27.2 35.6 45:0 59.2 60.9 84.7 burn — — — — C E 113.4 19.7 25.3 33.2 37.7 66.9 74.7 burn — — — — C E 2 13.5 16.2 21.327.9 38.6 burn — — — — — —

[0081] TABLE 3 Dynamic Thermal Stability Example Time/minutes 2 45.9 344.6 Con 1 55.1 Con 2 14.0 CE 1 25.7 CE 2 12.6

EXAMPLE 4

[0082] A general flexible PVC formulation containing: INGREDIENT AMOUNTPVC resin (k = 70) 100.0 parts Dioctyl phthalate  40.0 phr Epoxidizedsoybean oil  5.0 phr Stearic acid  0.2 phr Stabilizer See Table 4

[0083] was processed on a dynamic two-roll mill at 350° F. to give aseries of 45 mil thick sheets. A drop of a material having a knownsurface tension was placed on each sheet and the advancing contact angleof each drop was quantified with a goniometer at 24° C.. The cosine ofthe contact angle was plotted against the surface tension of each drop.The line was extrapolated to cosine=1 (critical surface tension). Theresults are given in Table 5 where Sheets A-E were made from theformulations shown in Table 4. TABLE 4 Example Stabilizer Amount (phr) %metal Comp Ex 3 DHP/2-MET 2.00 0.0 Sheet A Zinc octanoate (18% Zn) 0.050.5 Example 5 DHP/2-MET 2.00 Sheet B ZNION 0.75 0.5 Comp Ex 4 Calciumstearate 2.00 6.5 Sheet C Zinc octanoate (18% Zn) 0.05 0.5 Comp Ex 5Commercial Ba/Zn/P 2.00 9.0 Sheet D Comp Ex 6 Commercial Ca/Zn 2.00 3.0Sheet E

[0084] TABLE 5 PVC Sheet Surface tension (±0.5 dyne-cm) A 22.0 B 25.6 C22.0 D 21.3 E 21.2

[0085] It can be seen that the stabilizer/adhesion promoter of thisinvention imparts an increase in the surface tension to the vinylsheets. This 20% increase in hydrophilicity makes the vinyl sheets moreamenable to coating with water-based inks.

[0086] The following examples show the utility in this invention oflatent mercaptans of Formula 1 wherein R¹ is a radical from an ester ofa glycol.

EXAMPLE 6 Preparation of Intermediate

[0087] A mixture of 736.16 grams (8 moles) of thioglycolic acid, 848.96grams (8 moles) of diethyleneglycol, and 1.3 grams of ptoluene sulfonicacid was heated to 80° C. at a pressure of 400 Torr in a reactorequipped with a mechanical stirrer, a thermometer, and a vacuum take-offcondenser. The refluxing temperature was held for 1 hour before thepressure was reduced to 120 Torr over a period of 2.5 hours to removewater formed by the esterification. The temperature rose to 120° C.asthe pressure was further reduced to 20 Torr over a period of 0.5 hour.The total weight of water removed was 140.92 grams. The product has anacid value of 12 and an SH content of 16.75% by weight. The yield was1421.12 grams. The product was a mixture of the diethyleneglycol mono-and diesters of thioglycolic acid (i.e.,hydroxyethyloxyethylmercaptoacetate and ethyloxyethyl dimercaptoacetate)and was satisfactory.

Preparation of Adduct

[0088] To the 1421 grams (7.89 equivalents) of intermediate thusproduced there was added 6.38 grams of AMBERLYST 15 ion exchange resinand then 708.21 grams (8.42 equivalents) of 3,4-dihydro(2H)pyran (DHP)was added dropwise over a period of 135 minutes under a nitrogen blanketat a temperature 40-50° C. After continued heating at 40-50° C. for 2.25hours, the %SH was 5.36. Another charge of DHP weighing 300.21 grams(about 3.5 moles) was added during a period of 0.5 hour and the reactionmixture was held at about 55° C. for 0.5 hour to reduce the % SH to3,32. After standing overnight (about 14 hours) under nitrogen, theproduct had an SH content of 2.68%.

[0089] The product was a mixture containing 2-S-(tetrahydropyranyl)hydroxyethoxyoxyethylthioglycolate, wherein R¹ ishydroxyethoxyethoxyacetylmethyl, andbis-[2-S-(tetrahydropyranyl)ethoxyethyl] thioglycolate, wherein R¹ isoxy[bis(ethoxyacetylmethyl)] and y is 2.

Preparation of Stabilizer

[0090] Said adduct and the zinc ionomer (or ZNION)described above aremixed to form an adhesion promoting stabilizer of this invention.

EXAMPLE 7 Preparation of intermediate

[0091] A mixture of 98.23 grams (1.07 moles) of thioglycolic acid,160.06 grams (1.07 moles) of triethyleneglycol, and 0.2 gram ofp-toluene sulfonic acid was heated to 100° C. at a pressure of 250 Torrin a reactor equipped with a mechanical stirrer, a thermometer, and avacuum take-off condenser. The refluxing temperature was held for 25minutes before the pressure was reduced to 10 Torr over a period of 1.5hours to remove water formed by the esterification. The productcontained the triethyleneglycol monoester (about 57% of the totalweight) and the triethyleneglycol diester of thioglycolic acid (about20%) and was satisfactory.

Preparation of Adduct

[0092] A mixture containing (2-S-tetrahydropyranyl)hydroxyethoxy-ethoxyethylthioglycolate andbis-(2-S-tetrahydropyranyl)ethoxyethoxyethyl di-thioglycolate wasprepared by cooling 100 grams (0.42 equivalent of SH) of the thusprepared mixture of triethyleneglycol mono- and diesters of thioglycolicacid along with 0.2 gram of AMBERLYST 15 ion exchange resin to 0° C. andadding 39.18 grams (0.462 mole) of DHP dropwise over a period of 30minutes. The mixture was held at 0° C. for 1 hour and then heatedgradually to room temperature (about 22° C.) and held there for 2 hours.The yield of product was 139.2 grams and the SH content was 3.5%.

Preparation of Stabilizer

[0093] Said adduct and the zinc ionomer (or ZNION)described above aremixed to form an adhesion promoting stabilizer of this invention.

EXAMPLE 8 Preparation of Intermediate

[0094] A mixture of 92.0 grams (1 mole) of thioglycolic acid, 212.21grams (2 moles) of diethyleneglycol, and 0.24 gram of p-toluene sulfonicacid was heated to 100° C. at a pressure of 200 Torr in a reactorequipped with a mechanical stirrer, a thermometer, and a vacuum take-offcondenser. The temperature was held for 0.5 hour before the pressure wasreduced to 10 Torr over a period of 1.9 hours and then held for 70minutes to remove water formed by the esterification. The temperaturewas raised to 110° C. as the pressure was further reduced to less than 1Torr over a period and held for 3 hours. The diethyleneglycol mono-esterof thioglycolic acid constituted 85.9% and the diester constituted 14.1%of the weight of the product. The SH content of the product was 19.49%by weight, which was satisfactory.

Preparation of Adduct

[0095] A mixture of 70 grams (0.412 equivalent) of the intermediate thusproduced and 0.15 gram of AMBERLYST 15 ion exchange resin was cooled toless than 0.5° C. and then 36.52 grams (0.434 equivalent) of DHP wasadded dropwise over a period of about 7 minutes and after 3 hours it waswarmed to room temperature (about 22° C.).

Preparation of Stabilizer

[0096] Said adduct and the zinc ionomer (or ZNION)described above aremixed to form an adhesion promoting stabilizer of this invention.

EXAMPLE 9 Preparation of Intermediate

[0097] A mixture of 188.85 grams (2.05 moles) of thioglycolic acid,154.26 grams (1.0 mole) of dithiodiglycol, and 5.1 grams of ptoluenesulfonic acid was heated to 110° C. in a nitrogen atmosphere for 2.5hours in a reactor equipped with a mechanical stirrer, a thermometer,and a vacuum take-off condenser to remove about 32 mls of water formedby the esterification. The SH content of the product was 20.6%. Thetheoretical SH content of the dithiodiglycol diester of thioglycolicacid is 21.9%).

Preparation of Adduct

[0098] A mixture of 15 grams (0.091 equivalent) of the intermediate thusproduced and 8.04 grams (0.096 equivalent) of DHP was stirred and 1 dropof 70% methane sulfonic acid caused an exothermic reaction which raisedthe temperature to 89° C. before cooling lowered it to 40° C. Thematerial was diluted with tetrahydrofuran and stripped at 35° C./2mm Hgfor 1 hour to give a product whose SH content was less than 0.1% and anacid number of 4.2.

Preparation of Stabilizer

[0099] Said adduct and the zinc ionomer (or ZNION)described above aremixed to form an adhesion promoting stabilizer of this invention.

EXAMPLE 10 Preparation of Intermediate

[0100] A mixture of 69.30 grams (0.752 mole) of thioglycolic acid, 50grams (0.367 mole) of pentaerythritol and 1.25 grams of p-toluenesulfonic acid was heated to 100° C. in a vacuum of about 200 mm Hg toremove water formed by the esterification. After 60 minutes, a gaschromatograph showed that the predominant product was the diester ofthioglycolic acid and was satisfactory. The removal of water wasfinished at 15 mm Hg.

Preparation of Adduct

[0101] The general procedure of Example 9 is followed to give thedesired oxy-bis(2-S-tetrahydropyranylthioglycolate) of pentaerythritolwherein R¹ of Formula 1 above is pentaerythrityl and y is 2.

Preparation of Stabilizer

[0102] Said adduct and the zinc ionomer (or ZNION)described above aremixed to form an adhesion promoting stabilizer of this invention.

[0103] The two hydroxyl groups of the thioglycolate may be complexedwith the zinc ion of a zinc halide to form a non-adhesion promoting heatstabilizer for a halogen-containing polymer. Said stabilizer may,however, be mixed with the adhesion-promoting stabilizer as an anotherembodiment of the invention claimed herein.

[0104] Articles of manufacture contemplated by this invention, e.g.packaging film and tubing are formed from the stabilized compositions ofthis invention by any of the well-known conventional techniques forforming polymers into shaped articles.

[0105] While a few specific embodiments of this invention have beendisclosed in considerable detail, variations and modifications of theseembodiments can be effected without departing from the spirit and scopeof the invention as disclosed and claimed herein.

The subject matter claimed is:
 1. A heavy metal-free, heat-stable PVCresin composition comprising a blocked mercaptan having the structure:

wherein a is 1, m is 0, and n is 0 or 1; y=1 to 4; R¹ is R′C(O)OH,wherein R′ is an alkylene radical having 2 or 3 carbon atoms, or R¹ isan alkyl, pentaerythrityl, alkylene, cycloalkyl, cycloalkylene, aryl,alkaryl, aralkyl, aralkylene, hydroxyalkyl, dihydroxyalkyl, alkoxyalkyl,acyloxyalkyl, hydroxy(polyalkoxy)alkyl, hydroxy(polyalkoxy)acyl, acyloxy(hydroxyalkyl), acyloxy (alkoxyalkyl.), acyloxy(polyalkoxy)alkyl,acyloxy(polyalkoxy)acyl, alkoxyacyl, oxy[bis (alkoxyacyl)], oxy[bis(polyalkoxyacyl)], benzoyloxy(polyalkoxy)alkyl,benzoyloxy(polyalkoxy)acyl, or alkylene bis-(acyloxyalkyl),thio-bis-[alkoxyacyl], dithio-bis-[alkoxyacyl], alkoxy(polyalkoxy)acyl,hydroxyalkoxyalkyl, alkoxy(hydroxyalkyl), alkoxy(polyalkoxy)alkyl,mercaptoalkyl, mercaptoalkylene , mercaptoalkoxyacyl,tetrahydopyranyloxy (polyalkoxy) acyl, tetrahydropyranyloxyalkyl,hydroxyaryl, or mercaptoaryl radical having from 1 to 22 carbon atoms;R², R³, R⁴, R⁵, R⁶, and R⁷ are independently hydrogen, a hydroxyl,mercapto, alkyl, alkylene, acyl, aryl, haloaryl, alkaryl, aralkyl,hydroxyalkyl, alkenyloxyalkoxy, alkoxy, aryloxy, alkaryloxy,mercaptoalkyl, hydroxyalkylmercaptoalkyl, mercaptoalkylene, hydroxyaryl,alkoxyaryl, alkoxyhydroxyaryl, arylcarbonyl, or mercaptoaryl radicalhaving from 1 to 22 carbon atoms; X is a heteroatom selected from thegroup consisting of oxygen and sulfur, and one or both of the R³ and R⁵alkylene radicals joins with R⁷ and X to form a heterocyclic moiety withX as the heteroatom; and as the sole metal-containing stabilizer, anamount of a zinc ionomer effective to improve the wettability bywater-based paints and inks of an article formed from the PVC resincomposition.
 2. The composition of claim 1 wherein X is oxygen and theresin is a flexible poly (vinyl chloride).
 3. The composition of claim 2wherein R¹ is acyloxyalkyl.
 4. The composition of claim 3 wherein R¹ isacyloxyethyl.
 5. The composition of claim 2 wherein the zinc ionomer isa mixed salt of a carboxylic acid having from 7 to 18 carbon atoms andan oxidized polyethylene.
 6. The composition of claim 3 wherein the zincsalt is a mixed salt of a carboxylic acid having from 7 to 18 carbonatoms and an oxidized polyethylene.
 7. The composition of claim 3wherein the acyloxy group contains from 12 to 18 carbon atoms.
 8. Thecomposition of claim 1 wherein the amount of the zinc ionomer is fromabout 0.2 to about 2.5 parts per hundred parts by weight of the resin.9. The composition of claim 8 herein the zinc ionomer is a mixed salt ofa carboxylic acid having from 7 to 18 carbon atoms and an oxidizedpolyethylene.
 10. The composition of claim 1 wherein the heterocyclicmoiety is tetrahydropyranyl.
 11. The composition of claim 1 wherein theheterocyclic moiety is tetrahydrofuranyl.
 12. The composition of claim 3wherein the heterocyclic moiety is tetrahydropyranyl.
 13. Thecomposition of claim 1 wherein the zinc ionomer comprises an oxidizedpolyethylene having a molecular weight of at least about
 750. 14. Thecomposition of claim 3 wherein the zinc ionomer comprises an oxidizedpolyethylene having a molecular weight of at least about
 750. 15. Thecomposition of claim 2 wherein R¹ is acyloxyethyl, the acyloxy moietycontains from 12 to 18 carbon atoms, the zinc ionomer is a mixed salt ofa carboxylic acid having from 7 to 18 carbon atoms and an oxidizedpolyethylene having a molecular weight of at least about 750 and an acidnumber of from about 2 to about 50, the amount of the zinc ionomer isfrom about 0.5 to about 1.5 phr, and the heterocyclic moiety istetrahydropyranyl.
 16. A heavy metal-free stabilizer for a poly(vinylchloride.) resin consisting essentially of from about 40% to about 80%by weight of a blocked mercaptan having the formula:

wherein a is 1, m is 0, and n is 0 or 1; y=1 to 4; R¹ is R′C(O)OH,wherein R′ is an alkylene radical having 2 or 3 carbon atoms, or R¹ isan alkyl, pentaerythrityl, alkylene, cycloalkyl, cycloalkylene, aryl,alkaryl, aralkyl, aralkylene, hydroxyalkyl, dihydroxyalkyl, alkoxyalkyl,acyloxyalkyl, hydroxy(polyalkoxy)alkyl, hydroxy(polyalkoxy)acyl,acyloxy(hydroxyalkyl), acyloxy(alkoxyalkyl), acyloxy(polyalkoxy)alkyl,acyloxy(polyalkoxy)acyl, alkoxyacyl, oxy[bis(alkoxyacyl)],oxy[bis(polyalkoxyacyl)], benzoyloxy(polyalkoxy)alkyl,benzoyloxy(polyalkoxy)acyl, or alkylene bis-(acyloxyalkyl),thio-bis-[alkoxyacyl], dithio-bis-[alkoxyacyl], alkoxy(polyalkoxy)acyl,hydroxyalkoxyalkyl, alkoxy(hydroxyalkyl), alkoxy(polyalkoxy)alkyl,mercaptoalkyl, mercaptoalkylene, mercaptoalkoxyacyl,tetrahydopyranyloxy(polyalkoxy) acyl, tetrahydropyranyloxyalkyl,hydroxyaryl, or mercaptoaryl radical, said alkyl, alkylene, alkoxy, andacyl radicals having from 1 to 22 carbon atoms; R², R³, R⁴, R⁵, R⁶, andR⁷ are independently hydrogen, a hydroxyl, mercapto, alkyl, alkylene,acyl, aryl, haloaryl, alkaryl, aralkyl, hydroxyalkyl, alkenyloxyalkoxy,alkoxy, aryloxy, alkaryloxy, mercaptoalkyl, hydroxyalkylmercaptoalkyl,mercaptoalkylene, hydroxyaryl, alkoxyaryl, alkoxyhydroxyaryl,arylcarbonyl, or mercaptoaryl radical having from 1 to 22 carbon atoms;X is a heteroatom selected from the group consisting of oxygen andsulfur, and one or both of the R³ and R⁵ alkylene radicals joins with R⁷and X to form a heterocyclic moiety with X as the heteroatom; and a zincionomer.
 17. The stabilizer of claim 16 wherein R¹ is acyloxyethyl, theacyloxy moiety contains from 12 to 18 carbon atoms, the zinc ionomercomprises a mixed salt of a carboxylic acid having from 7 to 18 carbonatoms and an oxidized polyethylene having a molecular weight of at leastabout 750, X is oxygen, and the heterocyclic moiety istetrahydropyranyl.
 18. A method for improving the water wettability of aPVC article which comprises mixing a vinyl chloride resin with a latentmercaptan having the formula:

wherein a is 1, m is 0, and n is 0 or 1; y=1 to 4; R¹ is R′C(O)OH,wherein R′ is an alkylene radical having 2 or 3 carbon atoms, or R¹ isan alkyl, pentaerythrityl, alkylene, cycloalkyl, cycloalkylene, aryl,alkaryl, aralkyl, aralkylene, hydroxyalkyl, dihydroxyalkyl, alkoxyalkyl,acyloxyalkyl, hydroxy(polyalkoxy)alkyl, hydroxy(polyalkoxy)acyl,acyloxy(hydroxyalkyl), acyloxy(alkoxyalkyl), acyloxy(polyalkoxy)alkyl,acyloxy(polyalkoxy)acyl, alkoxyacyl, oxy[bis(alkoxyacyl)],oxy[bis(polyalkoxyacyl)], benzoyloxy(polyalkoxy)alkyl,benzoyloxy(polyalkoxy)acyl, or alkylene bis- (acyloxyalkyl),thio-bis-[alkoxyacyl], dithio-bis-[alkoxyacyl], alkoxy(polyalkoxy)acyl,hydroxyalkoxyalkyl, alkoxy(hydroxyalkyl), alkoxy(polyalkoxy)alkyl,mercaptoalkyl, me rcaptoalkylene , mercaptoalkoxyacyl,tetrahydopyranyloxy(polyalkoxy)acyl, tetrahydropyranyloxyalkyl,hydroxyaryl, or mercaptoaryl radical having from 1 to 22 carbon atoms;R², R³, R⁴, R⁵, R⁶, and R⁷ are independently hydrogen, a hydroxyl,mercapto, alkyl, alkylene, acyl, aryl, haloaryl, alkaryl, aralkyl,hydroxyalkyl, alkenyloxyalkoxy, alkoxy, aryloxy, alkaryloxy,mercaptoalkyl, hydroxyalkylmercaptoalkyl, mercaptoalkylene, hydroxyaryl,alkoxyaryl, alkoxyhydroxyaryl, arylcarbonyl, or mercaptoaryl radicalhaving from 1 to 22 carbon atoms; X is a heteroatom selected from thegroup consisting of oxygen and sulfur, and one or both of the R³ and R⁵alkylene radicals joins with R⁷ and X to form a heterocyclic moiety withX as the heteroatom; with a zinc ionomer as the sole metal-containingstabilizer and heating the mixture to the incipient resin decompositiontemperature.
 19. The method of claim 18 wherein X is oxygen and R¹ isacyloxyalkyl.
 20. The method of claim 18 wherein the zinc ionomercomprises a mixed salt of a carboxylic acid having from 7 to 18 carbonatoms and an oxidized polyethylene.
 21. The method of claim 19 whereinthe acyloxy moiety of the acyloxyalkyl group contains from 12 to 18carbon atoms.
 22. The method of claim 18 wherein the amount of the zincionomer is from about 0.2 to about 2.5 parts per hundred parts by weightof the resin.
 23. The method of claim 22 wherein the zinc ionomer is amixed salt of an oxidized polyethylene and a carboxylic acid having from7 to 18 carbon atoms.
 24. The method of claim 19 wherein theheterocyclic moiety is tetrahydropyranyl.
 25. The method of claim 18wherein the heterocyclic moiety is tetrahydrofuranyl.
 26. The method ofclaim 18 wherein the zinc ionomer comprises a mixed salt of an oxidizedpolyethylene having a molecular weight of from about 750 to about 2100and an acid number of from about 2 to about
 50. 27. The method of claim19 wherein the zinc ionomer comprises a mixed salt of an oxidizedpolyethylene having a molecular weight of from about 750 to about 2100and an acid number of from about 2 to about. 50 and a carboxylic acidhaving from 7 to 18 carbon atoms.
 28. The method of claim 19 wherein R¹is acyloxyethyl in which the acyloxy moiety contains from 12 to 18carbon atoms, the heterocyclic moiety is tetrahydropyranyl, the zincionomer is a mixed salt of a carboxylic acid having from 7 to 18 carbonatoms and an oxidized polyethylene having an acid number of from about 2to about 50, and the amount of the zinc ionomer is from about 0.5 toabout 1.5 phr.
 29. A one-component PVC stabilizer consisting of acomplex of a zinc salt with a latent mercaptan as shown by the followingformula:

wherein Hal represents a halide ion.
 30. A PVC composition comprisingthe stabilizer of claim
 29. 31. A latent mercaptan having the followingformula:

wherein a is 0 or 1, m is 0 or 1, and n is 0 or 1; y=1 to 4, when y=1, zis 1 to 4, when y is more than 1 z is 1; R¹ is R′C(O)OH wherein R′ is analkylene radical having 2 or 3 carbon atoms, or R¹ is athio-[bis(alkoxyacyl)], dithio-[bis(alkoxyacyl)], pentaerythrityl,alkenyloxy(polyalkoxy)alkyl, oxy [bis (alkoxyacyl)], oxy [bis (polyalkoxyacyl], benzoyloxy(polyalkoxy)alkyl, or benzoyloxy(polyalkoxy)acylradical, said alkyl, alkylene, and acyl radicals having from 1 to 22carbon atoms; R², R³, R⁴, R⁵, R⁶, and R⁷ are independently hydrogen, ahydroxyl,. mercapto, alkyl, alkylenyl, acyl, aryl, haloaryl, alkaryl,aralkyl, hydroxyalkyl, chloroalkoxy, alkylene, alkenyloxyalkoxy, alkoxy,aryloxy, alkaryloxy, mercaptoalkyl, hydroxyalkylmercaptoalkyl,mercaptoalkylenyl, hydroxyaryl, alkoxyaryl, alkoxyhydroxyaryl,arylcarbonyl, or mercaptoaryl radical having from 1 to 22 carbon atoms;X is aryl, haloaryl, alkaryl, hydroxyaryl, dihydroxyaryl, aralkaryl,alkoxyaryl, arylcycloalkyl, or a heteroatom selected from the groupconsisting of oxygen and sulfur, with the option that one or both of theR³ and R⁵ alkylenyl radicals joins with R⁷ and X to form a heterocyclicmoiety with X as the heteroatom.
 32. A zinc ionomer-free compositioncomprising a PVC resin and the latent mercaptan of claim
 31. 33. A zincionomer-free composition comprising a PVC resin, the latent mercaptan ofclaim 31, and from about 0.005 to less than 0.5% of at least onesynergist selected from the group consisting of a metallic-based heatstabilizer and a Lewis acid, based on the weight of the PVC resin.
 34. Aheat-stable PVC resin composition comprising a blocked mercaptan havingthe structure:

wherein a is 0 or 1, m is 0 or 1, and n is 0 or 1; y=1 to 4, when y=1, zis 1 to 4, when y is more than 1 z is 1; R¹ is R′C(O)OH wherein R′ is analkylene radical having 2 or 3 carbon atoms, or R¹ is an alkyl,alkylene, pentaerythrityl, cycloalkyl, cycloalkylene, aryl, alkaryl,aralkyl, aralkylene, hydroxyalkyl, dihydroxyalkyl, alkoxyalkyl,acyloxyalkyl, hydroxy(polyalkoxy)alkyl, hydroxy(polyalkoxy)acyl,acyloxy(hydroxyalkyly, acyloxy(alkoxyalkyl), acyloxy(polyalkoxy)alkyl,acyloxy(polyalkoxy)acyl, alkoxyacyl, oxy[bis(alkoxyacyl)],oxy[bis(polyalkoxyacyl)], benzoyloxy(polyalkoxy)alkyl,benzoyloxy(polyalkoxy.)acyl., or alkylene bis-(acyloxyalkyl).,thio-bis-[alkoxyacyl], dithio-bis-[alkoxyacyl], alkoxy(.polyalkoxy)acyl,hydroxyalkoxyalkyl, alkoxy(hydroxyalkyl), alkoxy(acyloxyalkyl),alkoxy(polyalkoxy)alkyl, mercaptoalkyl, mercaptoalkylene.,tetrahydropyranyloxy(polyalkoxy) acyl, tetrahydropyranyloxyalkyl,hydroxyaryl, or mercaptoaryl radical having from 1 to 22 carbon atoms;R², R³, R⁴, R⁵, R⁶, and R⁷ are independently hydrogen, a hydroxyl,mercapto, alkyl, alkylene, acyl, aryl, haloaryl, alkaryl, aralkyl,hydroxyalkyl, chloroalkoxy, alkenyloxyalkoxy, alkoxy, aryloxy,alkaryloxy, mercaptoalkyl, hydroxyalkylmercaptoalkyl, mercaptoalkylenyl,hydroxyaryl, alkoxyaryl, alkoxyhydroxyaryl, arylcarbonyl, ormercaptoaryl radical having from 1 to 22 carbon atoms; X is phenyl,halophenyl, alkylphenyl, hydroxyphenyl, dihydroxyphenyl, alkoxyphenyl,phenylcyclohexyl, or a heteroatom selected from the. group consisting ofoxygen and sulfur, and one or both of the R³ and R⁵ alkylene radicalsjoins with R⁷ and X to form a heterocyclic moiety with X as theheteroatom; and a uracil having the formula:

wherein R* and R**, are independently hydrogen, alkyl, hydroxyalkyl, oralkoxyalkyl, and R*** is hydrogen, alkyl, phenyl, orhydroxyphenyl,wherein each of the alkyl moieties have from 1 to 4 carbonatoms, and optionally, as the sole metal-containing stabilizer, anamount of a zinc ionomer effective to improve the wettability bywater-based paints and inks of an article formed from the PVC resincomposition.
 35. A heat-stable PVC resin composition comprising ablocked mercaptan having the structure:

wherein a is 0 or 1, m is 0 or 1, and n is 0 or 1; y=1 to 4, when y=1, zis 1 to 4, when y is more than 1 z is 1; R¹ is R′C(O)OH wherein R′ is analkylene radical having 2 or 3 carbon atoms, or R¹ is an alkyl,alkylene, pentaerythrityl, cycloalkyl, cycloalkylene, aryl, alkaryl,aralkyl, aralkylene, hydroxyalkyl, dihydroxya l kyl, a l koxya l kyl,acyloxyalkyl, hydroxy(polyalkoxy)alkyl, hydroxy(polyalkoxy)acyl, acyloxy(hydroxyal kyl ), acyloxy ( alkoxyalkyl), acyloxy(polyalkoxy)alkyl.,acyloxy(polyalkoxy)acyl, alkoxyacyl, oxy[bis(alkoxyacyl)],oxy[bis(polyalkoxyacyl)], benzoyloxy(polyalkoxy) alkyl,benzoyloxy(polyalkoxy) acyl, or alkylene bis-(acyloxyalkyl),thio-bis-[aIkoxyacyl], dithio-bis-[alkoxyacyl], alkoxy(polyalkoxy)acyl,hydroxyalkoxyalkyl, alkoxy(hydroxyalkyl), alkoxy(acyloxyalkyl), alkoxy(polyalkoxy) alkyl, mercaptoalkyl, mercaptoalkylene,tetrahydropyranyloxy(polyalkoxy)acyl, tetrahydropyranyloxyalkyl,hydroxyaryl, or mercaptoaryl radical having from 1 to 22 carbon atoms;R², R³, R⁴, R⁵, R⁶, and R⁷ are independently hydrogen, a hydroxyl,mercapto, alkyl, alkylene, acyl, aryl, haloaryl, alkaryl, aralkyl,hydroxyalkyl, chloroalkoxy, alkenyloxyalkoxy, alkoxy, aryloxy,alkaryloxy, mercaptoalkyl, hydroxyalkylmercaptoalkyl, mercaptoalkylenyl,hydroxyaryl, alkoxyaryl, alkoxyhydroxyaryl, arylcarbonyl, ormercaptoaryl radical having having from 1 to 22 carbon atoms; R², R³,R4, R⁵, R⁶, and R⁷ are independently hydrogen, a hydroxyl, mercapto,alkyl, alkylenyl, acyl, aryl, haloaryl, alkaryl, aralkyl, hydroxyalkyl,chloroalkoxy, alkenyloxyalkoxy, alkoxy, aryloxy, alkaryloxy,mercaptoalkyl, hydroxyalkylmercaptoalkyl, mercaptoalkylenyl,hydroxyaryl, alkoxyaryl, alkoxyhydroxyaryl, arylcarbonyl, ormercaptoaryl radical having from 1 to 22 carbon atoms; X is phenyl,halophenyl, alkylphenyl, hydroxyphenyl, dihydroxyphenyl, alkoxyphenyl,phenylcyclohexyl, or a heteroatom selected from the group consisting ofoxygen and sulfur, and one or both of the. R³ and R⁵ alkylenyl radicalsjoins with R⁷ and X to form a heterocyclic moiety with X as theheteroatom; and a pyrrolodiazine dione described by the formula:

wherein R^(⋄), R^(2⋄), R^(3⋄), and R^(4⋄) are independently hydrogen orC₃-C₄ alkyl; and optionally, as the sole metal-containing stabilizer, anamount of a zinc ionomer effective to improve the wettability bywater-based paints and inks of an article formed from the PVC resincomposition.
 36. The composition of claim 35 wherein the pyrrolodiazinedione has the formula: